Wind farm

ABSTRACT

The present invention relates to wind farms, so called, comprising at least two wind turbines and in particular to offshore wind farms. In order to provide a wind farm in which transport between separate wind turbines can be effected more safely and with less dependence on weather, at least one cable connection  10  is provided between at least two of the wind turbines  12  of a wind farm, and a vessel  14  is disposed on said cable connection  10.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a wind farm comprising at leasttwo wind turbines and in particular to an offshore wind farm.

[0003] 2. Description of the Related Art

[0004] The wind turbines in wind farms are spaced from one another atsuch distances that any collision of blades is securely avoided evenwhen the wind turns direction, and the effects of one wind turbine onanother as a result of changing air flow conditions are kept as small aspossible. The distance between wind turbines is dependent on the radiusof the circle swept by the rotor of a wind turbine and, with rotordiameters in excess of 100 m now possible at the current state oftechnological development, the distance between wind turbines willincrease still further due to the even larger dimensions of new windturbines.

[0005] Depending on location and size, each wind turbine requiresmaintenance and the elimination of any malfunctions that may arise. Todo this, personnel and material must be transported to the wind turbine.

[0006] It is relatively easy to bring personnel and material to everywind turbine on land-based wind farms, whereas in the case of offshorewind farms this involves much greater effort and expense. The processcan be simplified by bringing people and goods, such as tools, spareparts, etc. to one place only, rather than having to call at eachseparate wind turbine on a wind farm.

[0007] The problem which then arises is that of distributing landedgoods, or generally of transporting goods and/or people between the windturbines of a wind farm, and particularly of an offshore wind farm.

[0008] Based on the premise that a wind farm has a central landing placewhere all goods and persons arrive or depart, the latter mustaccordingly be transported between the separate wind turbines of thewind farm.

[0009] A characteristic of offshore wind farms is that the weather thereis always rougher than on land. Winds can blow obstructed and quicklyreach high speeds.

[0010] Furthermore, waves of greater or lesser height must be expectedat all times. Therefore, transporting goods and ferrying people to theseparate wind turbines is not only unpleasant in many cases, but mayeven involve a considerable degree of risk.

[0011] The object of the present invention is therefore to provide awind farm in which transportation between the separate wind turbines canbe carried out safely and securely.

BRIEF SUMMARY OF THE INVENTION

[0012] This object is accomplished according to the invention by a cableconnection between at least two of the wind turbines and by a gondoladisposed on said cable connection. Transportation of people and goodsbetween the wind turbines can be achieved with said gondola.Advantageous embodiments for other wind farm structures are described inthe following.

[0013] The cable connection is preferably spanned at such a height thatit neither impinges on the rotor diameter of the wind turbine nortouches the crests of waves, even when the waves are high.

[0014] A deflection member for the cable connection can be provided oneach wind turbine, such that the cable connection is spanned as anendless cable loop between the deflection members and the gondola isfixedly connected to the cable connection. By this means, the gondolacan be driven in the desired direction by moving the cable connection,and the structure is kept very simple.

[0015] When there are two wind turbines connected to each other, thecable connection travels around the deflection member at each windturbine and back to the other wind turbine. When the cable connectionconnects at least three wind turbines with each, the deflection memberon the middle wind turbine serves as a support, and the cable connectionis guided onwards to the respective outer wind turbine.

[0016] The cable connection can be moved by means of a motor, andpreferably by an electrically driven motor. This is particularlyadvantageous, because electrical energy is generated in the wind farmand is therefore readily available, thus obviating the need to transportother energy carriers, such as fuel. Electric motors can also becontrolled in a simple manner.

[0017] The cable connection suitably comprises a main cable and atraction cable. Although the gondola is mounted on the main cable, it isable to travel in relation to said main cable. The traction cable isattached to the gondola. When the traction cable is pulled in thedesired direction of travel, the gondola moves along the main cable inthe desired direction. This traction on the traction cable can beprovided by a motor. Electrical energy is advantageously used as thedrive energy.

[0018] The deflection member preferably comprises two independentlyrotatable deflection pulleys, whereby the main cable is guided over oneroller and the traction cable over the other roller. The traction cablecan be configured as a circulating endless cable loop, whereas the maincable can be provided only once along the stretch travelled by thegondola. Due to the endless traction cable, it is sufficient to have areversible drive for the traction cable in order to drive the gondola inthe desired direction, and one can dispense with any reeling devices forthe traction cable at the two ends thereof.

[0019] In one particularly preferred embodiment of the invention, thegondola moves along the main cable under its own power. A motor driveand preferably an electromotor drive can be provided for this purpose,whereby the store of energy for driving the motor is provided in anenergy storage means in the gondola, for example in a battery.

[0020] A manual drive may be provided as an alternative to the motordrive, or as a supplementary emergency drive so that the gondola can bemoved in emergency operation even when there is a failure of the motoror the energy store.

[0021] In a particularly preferred embodiment of the invention, thedrive energy is supplied via the cable connection, the main cable, thetraction cable and/or a separate conductor line when the gondola isdriven electrically. By this means, control signals can also betransmitted to the gondola and/or a tower by remote control, for exampleto control the drive motor or a winch or the like.

[0022] In a preferred development of the invention, telemetry data, forexample, are transmitted via the electrical connection to a central windturbine or to several wind turbines. Furthermore, it is possible via thecable connection to process the communications, with each other and withthe gondola, of all the wind turbines in the wind farm between which thecable car is provided.

[0023] In an alternative embodiment of the invention, thesecommunications, that is to say, for example, the transmission oftelemetry data, control signals, etc. between separate wind turbines onthe wind farm and/or the gondola, can be effected at least in part bywireless transmission.

[0024] The cable connection can be structured in different ways. Asimple structure is based on the principle of a chain, in which all windturbines are connected to each other by the cable connection “like beadson a chain”. In this structure, the cable connection is a singlecontinuous cable connection that connects at least some of the windturbines in a predefinable series with each other.

[0025] However, the wind turbines may also be positioned in severalrows, for example in three rows, and the cable connection follows, forexample, a path in the shape of the letter “S” between the wind turbinesto connect the wind turbines with each other.

[0026] An alternative variant of the cable system is a star-shapedarrangement of the cable connection, starting from a central windturbine representing, for example, a central landing place, so that allother wind turbines can be reached by the shortest possible path.

[0027] Another variant is a networked cable system that not onlyprovides shortest possible connections from a central wind turbine tothe other wind turbines, but also forms relatively short stretchesbetween all the wind turbines.

[0028] In order to keep the horizontal displacement of the gondola onthe cable connection low while the gondola is travelling between thewind turbines of a wind farm, or to prevent such displacement withincertain limits, the wind farm according to the invention has, in apreferred development, a holding cable that is provided at a predefinedvertical distance parallel to the cable connection. The distance isdimensioned in such a way that the gondola is guided between the cableconnection and the holding cable. In this arrangement, the cableconnection is preferably above the gondola, and the holding cable isbelow the gondola.

[0029] In a particularly advantageous development of the invention, one(upper) part of the endless cable loop in a cable connection configuredas an endless loop can carry the gondola, while the other (lower) partof the endless cable loop performs the function of the holding cable.

[0030] In an alternative embodiment, a flywheel mass rotating about avertical axis is used to stabilize the gondola. Said flywheel mass isdriven by a motor and acts as a gyroscope to counter any horizontaldisplacement of the gondola.

[0031] Preferably, each wind turbine of the wind farm has a closeabledoor in its tower. Said door is generally located at the height at whichthe gondola reaches the wind turbine. This enables loading activities tobe performed without having to overcome a difference in height.

[0032] In another preferred development, the wind turbines and thegondola have a locking device that permits the loading and unloadingposition of the gondola to be prescribed, such that swinging movementsof the gondola relative to the tower of the wind turbine are preventedwhen the gondola is in said position. The locking device is preferablyconfigured in such a way that one part of the locking device is providedclose to the door on the tower of the wind turbine, and the other partat a suitable position on the gondola. A particularly preferredembodiment is one in which the locking device is a two-point lockingdevice, in order to avoid the formation of a pivotal point that occurswhen locking operates at one point only.

[0033] Preferably, said locking device can function electromagneticallyand be switched on and off by operating a switch inside the tower and/orfrom the gondola. This enables convenient and secure handling withoutthe risk of injury as a result of a swinging gondola that may, forexample, collide with the tower due to wind action.

[0034] In one preferred development of the invention, the locking devicecan be remotely controlled, and it is particularly preferred for it tobe remotely controllable from the gondola so that manual operation canbe avoided. By this means, the latent risk of injury when operating thelocking device is further reduced.

[0035] A particularly preferred embodiment is one in which a cover ofsubstantially horizontal extension is mounted above the opening on atleast one wind turbine, said cover bearing a protective wall extendingsubstantially vertically and at a predefined distance parallel to thecable connection. By means of the cover and the protective wall, whichenclose a predefined angle, a protective roof is formed that protectsthe gondola when in the area of the opening as well as the openingitself against weather. The gondola and the opening are protected by thetower itself, on the one hand, and by the protective roof, on the other,such that the gondola is shielded against the wind and is not pushedagainst the tower.

[0036] If the protective roof is made long enough, displacement of thegondola and hence a potential collision with the tower can be avoidedeven when the wind or wind vectors are transverse to the direction inwhich the gondola is travelling.

[0037] The horizontal spacing between the outer ends of the firstprotective wall and the tower is preferably greater than the horizontalspacing to the central portion of the protective wall. In this way,collisions between the gondola and the protective wall are preventedeven when the gondola is horizontally displaced towards the protectivewall, for example by cross winds.

[0038] In one preferred development of the invention, additionalprotective walls can be attached to the tower on both sides of theopening parallel to the first protective wall and at the same height,said additional walls extending the area in lee of the tower such that awind vector transverse to the direction in which the gondola istravelling does not push the latter against the outer protective wall.The horizontal distance between the protective walls at the tower can besubstantially equal to the width of the gondola and enlarge towards thelateral ends of the protective walls, such that a horizontaldisplacement of the gondola in the entry area between the protectivewalls does not lead to collisions between the gondola and one of theprotective walls.

[0039] The gondola itself can preferably be fitted with elastic coatingat each of the corners on the lower portion of the gondola cabin, andhence at those points that will be affected first in the event that acollision with other facilities of the wind farm occurs as a result ofthe gondola being horizontally displaced. On the one hand, said coatingsdampen any collision that might occur, thus preventing damage occurringto the gondola and other facilities of the wind farm, and on the otherhand they serve as buoyancy aids to keep the gondola buoyant in theevent of an accident.

[0040] At the same time as, or in place of the elastic coating on thegondola, such a coating may also be provided on the protective walls,especially in the entry area and at a height at which a horizontallydisplaced gondola first collides with the protective wall. Aparticularly preferred embodiment is one in which a first gangboard isprovided at the second protective wall, said gangboard having aretention facility, such as a railing, all around it. In oneadvantageous development of the invention, the gangboard extends overthe entire length of the protective wall and is attached in such a waythat it can be reached from the opening.

[0041] By this means, the outer side of the gondola can be reached inorder to perform repair work and/or maintenance and cleaning work, forexample. If the second protective wall is present, the gangboard can bedelineated on one side by said protective wall, and a retention facilitycan be dispensed with there.

[0042] It is particularly preferred to provide a second gangboardparallel to the first on the first protective wall. Said secondgangboard, too, has a retention facility on the sides which are notadjacent to the first protective wall.

[0043] As a further preferred embodiment, a transverse gangboard can beprovided at at least one outer end of the first and second gangboards,wherein said transverse gangboard bridges the gap between thesubstantially parallel first and second gangboards.

[0044] To enable unobstructed entry and exit of the gondola, thetransverse gangboard can be pivotably coupled at one of its ends andpivoted upwards about its pivot axis in order to clear the way for thegondola to pass through. In one advantageous development of theinvention, such transverse pivotable gangboards are coupled at both endsof the first or the second gangboard, thus enabling all sides of thegondola to be reached from the outside.

[0045] The gap between one transverse gangboard and the other ispreferably selected so that it is substantially equal to the relevantdimensions of the gondola. In one particularly preferred development ofthe invention, at least one of the transverse gangboards is slideablealong its pivotal axis, such that the distance between the transversegangboards can be altered and hence adjusted to the respectiverequirements.

[0046] On at least one wind turbine tower, a hoisting apparatus can beprovided, preferably under the protective roof, said hoisting deviceenabling the handling of heavy freight, on the one hand, and, on theother hand, the handling of the gondola and gondola parts, for examplefor repairs. By means of such a hoisting apparatus, provided it isdesigned for an appropriate load, the entire gondola can be hoisted sothat the underside of the gondola can be reached from the gangboard forrepair, maintenance and cleaning purposes.

[0047] In one alternative embodiment of the invention, a suitablymounted single- or multi-part working platform can be provided in placeof gangboards in order to reach the outer sides of the gondola. To thisend, the area of the working platform can have a minimum size thatenables all sides of the gondola to be accessed from the outside.

[0048] In another alternative embodiment of the invention, a workingcage or a crown safety platform can be provided, wherein said cage orplatform can be moved and/or pivoted such that the outer sides of thegondola can be reached. The crown safety platform, like the workingplatform, is enclosed on all sides by a retention facility in order toprevent any unintentional fall from the platform or cage on the part ofpersonnel working thereon.

[0049] In one particularly preferred embodiment of the invention, thedoor is larger than the cross section of the gondola, and the cablesystem extends into the tower of the wind turbine. This is achieved byhaving at least one set of points at each tower along the cableconnection. In this way, the gondola can travel through the opened doorin the tower and be loaded and/or unloaded therein regardless of weatherconditions.

[0050] A closed gondola provides for transportation of people and goodsin such a manner that they are substantially protected against theweather. In one particularly preferred development of the invention, thegondola is configured so that it has a closeable exit opening throughwhich the guide with which the gondola is suspended from the cableconnection and guided can be reached.

[0051] In order to avoid the loss of the gondola in the event of itfalling from the cable, the gondola is preferably designed to bebuoyant, and can dispose of signalling means such as signal guns, flaresor the like, as well as buoyancy aids such as automatic self-inflatingfloat rings. These buoyancy aids increase the buoyancy of the gondola sothat it remains buoyant even when loaded. In one preferred developmentof the invention, the gondola has righting aids that at least make itmore difficult for the gondola to overturn, or indeed prevent it fromdoing so.

[0052] In order to effect monitoring of operation, or at leastsemiautomatic control of the cable car system, a central control deviceas well as a plurality of sensors and/or actuators are provided. Thesensors and/or actuators can be connected to the central control devicevia an interface.

[0053] By means of sensors connected thereto, the central control devicecan thus identify, on the one hand, certain operating parameters andstates, for instance the position of the gondola, its operating speed,the horizontal displacement, the weight of the gondola, the rotationalspeed of a flywheel mass, the amount of energy stored, motor operationaldata, the openings in the towers (closed, open, . . . ), etc. Of course,telematics data can also be captured by sensors in the machine house ofa wind turbine and subsequently processed.

[0054] By means of the actuators provided, the central control unit isable to influence operating parameters and states. This can involve, forexample, controlling the locking device between the gondola and thetower, depending on the position of the gondola relative to the tower,or controlling the lighting under the protective roof, or controllingposition lights (insofar as any are provided on the towers and/or otherparts of the wind farm) depending on brightness, or automaticallyreleasing or operating doors, or influencing the speed of the gondola,including bringing it to a stop.

[0055] In one alternative embodiment of the invention, the controlsystem can be decentralized. To this end, separate control systems canbe provided in at least two of the wind turbines on a wind farm, saidsystems communicating with each other and with the gondola. In this way,operating parameters and states can similarly be identified andanalysed. Each control system can be connected with a predefinableportion of the sensors and/or actuators. One advantage of thisdecentralized solution is the redundancy thus provided, such that in theevent of a control unit failure, neighboring control units can take overits functions.

[0056] In one particularly advantageous development of the invention,support masts are provided between wind turbines on a wind farm in orderto support the cable connection and in this way prevent excessive sag ofthe cable connection between the towers, as well as the loads that canensue as a result of large spans between the towers of the wind turbineson a wind farm.

[0057] The wind farm according to the invention is preferably equippedwith at least one accommodation area for accommodating at least oneperson. The space within said accommodation area is preferably organizedinto different functional areas, such as a sanitation area and/or akitchen area and/or a pantry area and/or a rest area, and it isparticularly preferable that it be integrated into the tower of a windturbine.

[0058] In one alternative embodiment of the invention, the accommodationarea is located separately from the wind turbines but within the windfarm. This location can be a separate platform, for example, or canpreferably be on a platform mounted on a tower of a wind turbine.

[0059] Said platform can serve additional functions, such as those of ahelicopter pad and/or a ship's berth.

[0060] Due to the limited area inside the tower, the accommodation areain a preferred development of the invention is distributed among severalinterconnected levels inside the tower. Within the accommodation area,equipment for communicating and signalling predefined data are provided.Said signalling may include acoustic and optical signalling, or anappropriate way of recording the data.

[0061] Communication includes voice and/or data communication on wire orwireless communication links, on the one hand with remote stationsoutside the wind farm, such as remote operations or maintenance centers,and on the other hand with remote stations inside the wind farm, such asother wind turbines or the gondola of the cable car system.

[0062] In a particularly preferred embodiment of the invention,communication also includes influencing predefined operating parametersof the wind farm facilities, as well as surveillance and control of windfarm operation. By this means, a continuously manned monitoring stationcan be created on the wind farm according to the invention, whichmonitoring station can respond immediately in the event of faults orfailures occurring, and can take or initiate appropriatecounter-measures.

[0063] In one particularly preferred development of the invention, awater treatment plant for supplying the personnel with drinking waterand service water is provided, said plant being operated with electricalenergy generated on the wind farm. To bridge gaps in supply due, forexample, to windless conditions, a suitably dimensioned energy storagemeans is provided to ensure that emergency operations at least aremaintained in order to continue supplying the accommodation area withenergy and water.

[0064] The energy storage means used for this purpose can be storagemeans for electrical power, such as capacitors, chemical means of energystorage, such as batteries, or storage means for hydrogen which arecharged with hydrogen obtained from seawater by electrolysis, and fromwhich electrical energy can be obtained in a fuel cell.

[0065] In one particularly preferred embodiment of the invention, atleast the wind turbine equipped with the accommodation area includesequipment for weather observation, and/or for detecting, analysing,recording and/or forwarding meteorological data. Furthermore, the windturbine or additional wind turbines in the wind farm can performfunctions as navigational aids for shipping, for example in the form ofa sea marker or as a station for providing (first) aid to personsinvolved in accidents, or to shipwrecked persons.

[0066] In one development of the invention, at least one wind turbineequipped with an accommodation area has a viewing platform provided onthe tower of the wind turbine below the machine house. Said viewingplatform can encircle the tower of the wind turbine either completely,or at least partially in a preferred direction, and be fitted withwindows that enable the surrounding area to be monitored. Said viewingplatform can also be equipped with devices for signalling data, forinfluencing predefined operating parameters and/or for communication.The wind turbine with the viewing platform is positioned within the windfarm in such a way that a maximum number of the wind turbines in thewind farm can be seen from that position.

[0067] The viewing platform can be provided in close physical proximityto the accommodation area, or form an integral part thereof.Alternatively, the viewing platform and the accommodation area can bespatially separated, with the accommodation area located below theviewing platform near the base of the tower in order to permit moregenerous dimensions of the rooms, whereas the viewing platform islocated immediately below the machine house to enable good observationof the surroundings.

[0068] If the distance between the viewing platform and theaccommodation area is large, an elevator can be provided inside thetower to save time when making several trips a day between the viewingplatform and the accommodation area, on the one hand, and to limit thephysical burden on the personnel, on the other hand. The elevator can beequipped with an emergency telephone facility so that help can be calledin the event of the elevator breaking down.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

[0069] One embodiment shall now be described in detail with reference tothe figures. These show:

[0070]FIG. 1 a first variant of the cable system on a wind farm;

[0071]FIG. 2 a second variant of the cable system on a wind farm;

[0072]FIG. 3 a third variant of the cable system on a wind farm;

[0073]FIG. 4 the path of the cable connection between two wind turbines;

[0074]FIG. 5 an alternative cable arrangement;

[0075]FIG. 6 suspension and drive of the gondola by means of a maincable and a traction cable;

[0076]FIG. 7 a plan view of a wind turbine with a protective roof; and

[0077]FIG. 8 a side elevation view of the tower with the protectiveroof.

DETAILED DESCRIPTION OF THE INVENTION

[0078]FIG. 1 shows a wind farm comprising nine wind turbines 12. Windturbines 12 are arranged in three rows, each comprising three windturbines 12 and connected with each other by a cable connection 10 insuch a way that the gondola 14 can reach the separate wind turbines 12separately and consecutively. Thus, when travelling from one end of thecable connection 10 to the other end of the cable connection 10, thegondola 14 always passes all the wind turbines 12 on the wind farm.

[0079] The cable connection 10 can be an endless cable loop on which thegondola 14 is fixedly disposed. Therefore, when the cable moves, thegondola 14 is inevitably moved as well.

[0080] If the endless cable loop lies in a substantially horizontalplane, the cable can be driven in a constant direction at all times, inthe simplest case, and the gondola 14 moves in the opposite directionafter passing the deflection point, thereby being shifted by thehorizontal dimension of the endless cable loop.

[0081] However, since this also applies when travelling from one windturbine 12 to an adjacent wind turbine 12 in the opposite direction, itmay be necessary to pass all the other wind turbines of the wind farmsuch that the gondola must travel almost twice the length of the cableconnection 10.

[0082] For example, if the gondola 14 is located at the wind turbinemarked A and must now travel to the wind turbine marked B, it must firsttravel, in the case of a unidirectional cable drive, to the wind turbinemarked C and from there back to the destination wind turbine marked B.In doing so, it travels the entire length of the cable connection almosttwice.

[0083] If it is possible to drive the cable connection in twodirections, all that is needed for the trip from A to B is a reversal ofthe direction of travel and a short trip between two wind turbines.

[0084] If the cable connection 10 is an endless cable connection in asubstantially vertical plane, a means for driving the cable connection10 in two directions is absolutely essential, since otherwise thegondola fixedly attached to the cable connection 10 would get into ahazardous situation at the latest on reaching the reversal point on theendless cable loop.

[0085] For this reason, sensors 44 are provided on the wind turbinesmarked B and C in the figure, wherein said sensors identify when theirposition is reached by the gondola 14, and thus initiate a stop orredirection procedure. For the sake of simplicity, these sensors areshown as switches. Other types of sensor, such as Hall sensors, opticalsensors, etc., are also suitable, of course, for determining whether thegondola 14 has reached this position. Of course, the position of thesensors is chosen so that there is still sufficient stopping distanceeven when the gondola 14 is loaded.

[0086]FIG. 2 similarly shows a wind farm comprising nine wind turbines12 arranged in three rows each with three wind turbines 12. In thisarrangement, there is a central wind turbine 12 that can have specialdocking and storage facilities, for example. Radiating from this centralwind turbine 12, there is a star-shaped arrangement of cable connections10 connecting to all the other wind turbines 12 of the wind farm. Thisresults in the shortest possible paths for the gondola 14 (not shown inthis figure) to reach the other wind turbines 12—each measured from thecentral wind turbine 12.

[0087] However, a trip from one of the non-central wind turbines 12 toanother non-central wind turbine 12 always leads firstly to the centralwind turbine 12 and onwards from there to the destination wind turbine12.

[0088] Also shown in this figure is a support mast 11 at a cableconnection 10. Said support mast 11 supports the cable connection 10,thus preventing excessive sag of the cable connection 10 in the case oflarge spans between two wind turbines 12.

[0089] This sag results from the cable connection's own weight.Depending on the properties of the cable connection 10, there is amaximum distance between two support points for the cable connection 10,which if exceeded may result in the cable connection 10 severing underits own weight. However, even with a lower spacing between the supportpoints, the sag in the cable connection 10 may already be too great,causing the gondola 14 to come too close to the water surface.

[0090] This could be counteracted, theoretically, by having a highertension in the cable connection 10. However, if a higher tension in thecable connection arises due to the effect of cold temperatures, thetensile strength may be exceeded and the cable connection 10 will sever.In other words, depending on the material used, a certain amount of sagin the cable connection 10 is unavoidable. By using support masts 11,these problems can be solved.

[0091]FIG. 3 shows the same arrangement of wind turbines 12 as in FIGS.1 and 2. The difference again consists in the structure of the cableconnection 10 between the wind turbines 12. In FIG. 3, the structure islike that of a network, such that each wind turbine 12 forms a node inthe network. By means of this cable structure, even shorter distancesensue for particular stretches over which the gondola 14 (not shown inthe figure) can reach particular wind turbines 12.

[0092] In this figure, too, a support mast 11 is provided for a largespan between two wind turbines 12 in order to limit the sag and thetension in the cable connection 10. Of course, support masts 11 can beused in any segment of the cable connection 10 between two wind turbines12, in order to gain additional support points for the cable connection10.

[0093]FIG. 4 shows two wind turbines 12 that are connected with eachother by a cable connection 10. The upper portions of the towers havebeen left out in the figure, although the lower edge of the area sweptby the rotors is shown by a broken line 30. Each of the towers has anopening 18 that can be closed with a door, and from each opening aladder 32 is provided that leads to the base of the tower. The opening18 in the tower is provided at the height at which the gondola 14reaches the tower.

[0094] Above the opening 18 on each tower, a deflection member 16 isprovided through which the cable connection 10 is guided. The gondola 14is located on said cable connection 10. Depending on the embodiment ofthe cable connection 10, the gondola 14 is carried and/or driven by thecable connection, or the gondola 14 moves under its own power along thecable connection 10.

[0095] In the example shown, a drive motor 15 is located on the tower ofa wind turbine above the deflection pulley 16, said drive motor beingable to drive the cable connection 10 in appropriate manner in the caseof a gondola 14 that is not self-propelled.

[0096] In the lower part of the gondola 14 there is an additionalcompartment 26 that is separated from the gondola cabin by the floor ofthe latter. Inside said compartment 26 there is a flywheel mass 28 whichby means of a drive motor is kept at a high speed of rotation about itsrotational axis, shown as a broken line. As a result of this rotation,the flywheel mass 28 acts as a gyroscope and stabilises the gondola 14in its position by counteracting any horizontal displacement on the partof the gondola 14. By this means, the gondola 14 is stabilised whiletravelling and displaced to only a limited extent, even when cross windsoccur.

[0097] The drawing in FIG. 5 similarly shows two towers of wind turbines12, the upper portions of which have been omitted from the figure.However, the lower portion of the area swept by the rotors is againshown. In the towers, the closeable openings 18 are shown at the heightat which the gondola reaches the wind turbine 12.

[0098] Above the opening 18 there are deflection members 16 throughwhich the cable connection 10 is guided. The gondola 14 is disposed onsaid cable connection 10 and can be made to travel between the windturbines.

[0099] Deflection members 16 are also provided below the openings 18. Bymeans of these additional deflection members 16, a further cableconnection in the form of a holding cable 24 is guided. Said holdingcable 24 runs at a predefined vertical distance 25 parallel to the cableconnection 10 and guides the gondola 14. By this means, the horizontalexcursion of the gondola 14 is limited, because it is guided both aboveand below by cables 10, 24.

[0100] The potential horizontal displacement of the gondola 14 variesaccording to the distance to the next wind turbine 12. When the distancebetween gondola 14 and wind turbine 12 decreases, the stabilising effectof deflection members 16 increases, and the potential horizontaldisplacement of the gondola 14 is accordingly lower, whereas when thedistance between the gondola 14 and a wind turbine 12 increases, theamount of sag in the cable connection 10 and the holding cable 24increases. In the middle of the stretch between two wind turbines 12,the sag is at its greatest, and hence the potential horizontaldisplacement of the gondola 14 is at its maximum.

[0101]FIG. 6 shows an enlarged view of the portions enclosed by a brokencircular line in FIG. 4 and FIG. 5. The cable connection 10 is formed bytwo cables 20, 22. The upper cable 20 is provided as a main cable andcarries the gondola 14 which is moveably disposed thereon with two guidesheaves 46. The lower cable 22 is a traction cable and is fixedlyattached to the gondola 14. By operating said traction cable 22, thegondola 14 can be moved in a suspended position along the main cable.

[0102]FIGS. 7 and 8 show a wind turbine 12 (FIG. 7) and a portion of thetower of the wind turbine 12 (FIG. 8) with a cover 34 of substantiallyhorizontal extension disposed thereon. FIG. 7 is a plan view and FIG. 8a side elevation view.

[0103] The cable connection 10 runs below said cover 34; the means bywhich it is suspended is not shown here for the sake of a betteroverview. Protective walls 36 are disposed on each of the two sides ofthe cover 34 that run parallel to the cable connection 10.

[0104] In combination with the cover 34, these protective walls 36 forma protective roof that protects the gondola 14 and the opening 18 in thetower of the wind turbine 12 against the weather. Said protective roofextends on both sides of the opening 18, parallel to the cableconnection 10.

[0105] Due to the fact that, while the gondola is travelling between twowind turbines 12, horizontal displacement of the gondola 14 is possibleat all times, albeit limited in respect of amount and direction, theouter ends of the protective roof are widened. The spacing between theprotective walls 36 increases in predefined portions of the protectiveroof with increasing distance from the opening 18. In the middleportion, near the opening 18, the dimensions of the protective roof canbe substantially equal to those of the gondola 14.

[0106] By means of the greater spacing between the protective walls 36,the gondola 14 can be moved between the protective walls and hence intotheir lee side, even when, for example, the gondola is horizontallydisplaced by cross winds. Owing to the shelter from the wind thusprovided, the gondola 14 is no longer displaced and for this reason thespacing between the protective walls 36, 38 can be made smaller.

[0107] Elastic coatings 48 are provided on the protective walls 36, 38in the entry area, said coatings being intended to dampen any collisionof the gondola 14 with the protective walls 36, 38 in such a way atleast that no significant damage occurs. Independently of these coatings48 on the protective walls 36, 38, similar coatings can be provided onthe gondola, for example in the form of fenders.

1. Wind farm comprising at least two wind turbines, characterised by acable connection (10) spanning at least two wind turbines (12) at apredetermined height, and a gondola (14) disposed on said cableconnection.
 2. Wind farm according to claim 1, characterised by a cableconnection (10) spanned as an endless cable loop between deflectionmembers (16) at the wind turbines (12) and by a rigid connection betweenthe cable connection (10) and the gondola (14).
 3. Wind farm accordingto claim 1, characterised by a cable connection (10) comprising a maincable (20) and a traction cable (22) and a gondola (14), the gondolabeing moveably connected to the main cable (20) and fixedly connected tothe traction cable (22).
 4. Wind farm according to claim 3,characterised by a traction cable (22) extending as an endless cableloop along the deflection members (16).
 5. Wind farm according to one ofclaims 3 or 4, characterised by deflection members (16) having twoindependently rotatable deflection pulleys.
 6. Wind farm according toone of claims 3 to 5, characterised by the traction cable (22) beingdriven by a motor.
 7. Wind farm according to claim 1, characterised by agondola (14) that moves along the cable connection (10) under its ownpower (14).
 8. Wind farm according to claim 7, characterised by at leastone motoric drive for moving the gondola (14) along the cable connection(10), wherein the drive is preferably an electrical drive.
 9. Wind farmaccording to claim 8, characterised by the gondola drive receiving adrive power supply from a store of energy carried in the gondola (14).10. Wind farm according to one of the claims 7 to 9, characterised by atleast one manually operable drive for moving the gondola (14) along thecable connection (10).
 11. Wind farm according to one of claims 7 to 9,characterised by a remotely controllable drive for moving the gondola(14).
 12. Wind farm according to claim 11, characterised by use of atleast one portion of the cable connection (10) as an electricalconductor.
 13. Wind farm according to claim 12, characterised by a cablewhich is integrated into the cable connection (10).
 14. Wind farmaccording to one of claims 1 to 13, characterised by a star-shapedarrangement of cable connections (10) between a specified wind turbine(12) and the other wind turbines (12).
 15. Wind farm according to one ofclaims 1 to 13, characterised by a networked arrangement of cableconnections (10) between the wind turbines (12), wherein each windturbine (12) forms a node in the network.
 16. Wind farm according to oneof claims 1 to 13, characterised by a single cable connection (10)between the wind turbines (12) of the wind farm, said cable connectionconnecting at least one portion of the wind turbines (12) in apredeterminable sequence.
 17. Wind farm according to one of claims 14 to16, characterised by a combination of at least two of the aforesaidsystems of cable connections (10).
 18. Wind farm according to one of thepreceding claims, characterised by a detachable locking device betweenthe gondola (14) and the tower of a wind turbine (12).
 19. Wind farmaccording to claim 18, characterised by a locking device configured as aholding magnet.
 20. Wind farm according to one of the preceding claims,characterised by a holding cable (24) extending parallel to the cableconnection (10) at a predefined distance therefrom.
 21. Wind farmaccording to one of the preceding claims, characterised by a cableconnection (10) extending at a predefined horizontal distance from thetower of the wind tower (12), and/or by a holding cable extending at apredefined horizontal distance from the tower (24).
 22. Wind farmaccording to one of claims 20 or 21, characterised by deflection members(16) on the wind turbines (12) for accommodating the holding cable (24).23. Wind farm according to one of claims 20 to 22, characterised in thatthe cable connection (10) is configured as an endless cable loop, andthat the holding cable (24) is part of said endless cable loop.
 24. Windfarm according to one of the preceding claims, characterised by agondola (14) with a flywheel mass (28) rotating about a vertical axis.25. Wind farm according to one of the preceding claims, characterised bya closeable opening (18) in the tower of a wind turbine (12) at theheight at which the gondola (14) reaches the tower.
 26. Wind farmaccording to claim 25, characterised by a locking device at the heightof the gondola near the opening (18).
 27. Wind farm according to one ofthe preceding claims, characterised by a cover (34) of substantiallyhorizontal extension disposed above the opening (18) on the tower of atleast one wind turbine (12).
 28. Wind farm according to claim 27,characterised by a first protective wall (36) disposed on the side ofthe cover (34) facing away from the tower, said protective wallextending substantially vertically and at a predefined distance parallelto the cable connection (10).
 29. Wind farm according to one of thepreceding claims, characterised by at least one second protective wall(38) disposed at the tower of the wind turbine (12) at the height of theopening (18) and extending substantially parallel to the cableconnection (10).
 30. Wind farm according to claim 29, characterised by atwo-part second protective wall (38) extending a predefined length onboth sides of the opening (18).
 31. Wind farm according to one of claims28 to 30, characterised by a gap between the first protective wall (36)and the second protective wall (38), said gap increasing in size in apredefined portion at a distance from the opening (18).
 32. Wind farmaccording to one of claims 28 to 31, characterised by an elastic coating(48) of predefined thickness on at least one of the protective walls(36, 38).
 33. Wind farm according to one of claims 27 to 32,characterised by at least one lighting installation on the cover (34)and/or the protective walls (36, 38).
 34. Wind farm according to one ofthe preceding claims, characterised by at least one gangboard extendingsubstantially parallel to the cable connection (10), said gangboardbeing reachable from the opening (18) and having at least one retentionfacility along its entire length.
 35. Wind farm according to one of thepreceding claims, characterised by a single- or multi-part workingplatform on the outside of the tower of at least one wind turbine (12),wherein said platform can be reached from the opening (18).
 36. Windfarm according to one of the preceding claims, characterised by a crownsafety platform or a working cage outside the tower of at least one windturbine (12), wherein said platform or cage can be reached from theopening (18).
 37. Wind farm according to one of the preceding claims,characterised by at least one first guide rail (40) disposed on thetower of the wind turbine (12) close to the opening (18) and extendingsubstantially parallel to the cable connection (10).
 38. Wind farmaccording to claim 37, characterised by a second guide rail (42)extending at a predefined distance substantially parallel to the firstguide rail (40).
 39. Wind farm according to one of claims 37 or 38,characterised by a gap between the first guide rail (40) and the secondguide rail (42), said gap increasing in size in a predefined portion ata distance from the opening.
 40. Wind farm according to one of claims 37to 39, characterised in that the guide rails (40, 42) support theprotective walls (36).
 41. Wind farm according to one of claims 25 to40, characterised in that the closeable opening (18) is larger than thegondola (14) and the cable connection (10) extends through the opening(18) into the inside of the tower of the wind turbine (12).
 42. Windfarm according to one of the preceding claims, characterised by at leastone set of points at each tower along the cable connection (10). 43.Wind farm according to one of the preceding claims, characterised byload anchoring facilities and lashing means in the gondola (14). 44.Wind farm according to one of the preceding claims, characterised by ahoisting device located on or in the gondola (14) for handling the loadbeing carried.
 45. Wind farm according to one of the preceding claims,characterised by a hoisting and/or transportation apparatus at or in thetower of at least one wind turbine (12).
 46. Wind farm according to oneof the preceding claims, characterised by a gondola (14) with anenclosed gondola cabin.
 47. Wind farm according to one of the precedingclaims, characterised by an elastic coating at at least one location onthe gondola (14) where the risk of collision with other wind farmfacilities is greatest.
 48. Wind farm according to one of the precedingclaims, characterised by a buoyant gondola (14).
 49. Wind farm accordingto one of the preceding claims, characterised in that the elasticcoating serves simultaneously as a float.
 50. Wind farm according to oneof the preceding claims, characterised by a control device comprising acentral control unit, sensors and/or actuators.
 51. Wind farm accordingto claim 50, characterised by the central control unit being disposed inone of the wind turbines (12) of the wind farm.
 52. Wind farm accordingto one of claims 50 or 51, characterised by at least one sensor thatdetects when the gondola (14) passes by.
 53. Wind farm according to oneof the preceding claims, characterised by a GPS module disposed in thegondola.
 54. Wind farm according to one of the preceding claims,characterised in that electrical energy generated in the wind farm isused to power the electrical drives.
 55. Wind farm according to claim54, characterised in that the energy is selectively drawn at thegenerator, at an intermediate DC circuit or at some other suitablepoint.
 56. Wind farm according to one of the preceding claims,characterised in that energy is transported within the wind farm atleast partially in a form other than electricity.
 57. Wind farmaccording to one of the preceding claims, characterised by masts (11)disposed adjacently between the towers of the wind turbines (12) forsupporting the cable connection (10).
 58. Method for controlling thecable car system provided between at least two wind turbines of a windfarm, characterised by evaluation by the central control unit of thesituation as detected by the sensors, and the triggering of appropriatecontrol signals for the actuators.
 59. Method according to claim 58,characterised by the transmission to the central control unit of GPSdata and/or data in other encoded form indicating the position of thegondola (14).
 60. Wind farm according to one of the preceding claims,characterised by least one wind turbine (12) having an accommodationarea for accommodating at least one person.
 61. Wind farm according toclaim 60, characterised by the accommodation area being equipped with asanitary area and/or a kitchen area and/or a pantry area and/or a restarea.
 62. Wind farm according to one of claims 60 or 61, characterisedby the accommodation area being integrated in the tower of a windturbine (12).
 63. Wind farm according to one of claims 60 to 62,characterised by the accommodation area being arranged in a plurality ofinterconnected levels.
 64. Wind farm according to one of claims 60 to63, characterised by a device for signalling predefined data and/or adevice for influencing predefined operating parameters within theaccommodation area.
 65. Wind farm according to one of claims 60 to 64,characterised by a communications facility for exchanging informationand/or data.
 66. Wind farm according to one of claims 60 to 65,characterised by a water treatment plant for supplying the personnelwith drinking water and service water.
 67. Wind farm according to one ofclaims 60 to 66, characterised by energy storage means for storingenergy to bridge gaps in power supply.
 68. Wind farm according to one ofclaims 60 to 67, characterised by devices for weather observation,and/or for detecting, analysing, recording and/or forwardingmeteorological data.
 69. Wind farm according to one of claims 60 to 68,characterised in that at least the wind turbine with the accommodationarea has navigational aids for shipping and/or equipment for helpinginjured or shipwrecked persons.
 70. Wind farm according to one of claims60 to 69, characterised by a viewing platform on the tower of the windturbine in which the accommodation area is located, said viewingplatform encircling the tower below the machine house either completely,or at least partially in a preferred direction.
 71. Wind farm accordingto claim 70, characterised in that at least part of the viewing platformhas windows to enable the surroundings of the wind turbine to bemonitored.
 72. Wind farm according to one of claims 70 or 71,characterised by an elevator between the accommodation area and theviewing platform.